The UN High Commissioner for Human Rights (UNHCR) has condemned the "outrageous" flogging of up to 35 young men and women in Iran last week after they were caught holding a graduation party together in Qazvin, north of Tehran.

According to official Iranian media, the students were arrested on May 26, interrogated and sentenced to 99 lashes each.

The UNHCR noted in a statement on May 31 that flogging is prohibited under international human rights law.

In its statement, the UNHCR said for Iranian authorities "to have meted out this cruel, inhuman and degrading punishment -- which could amount to torture -- is completely disproportionate and abhorrent."

The UNHCR said it was not an isolated incident.

It noted 17 mine workers were reportedly flogged in Western Azerbaijan Province in Iran earlier this month for protesting the dismissal of 350 workers at a gold mine.

The UNHCR said a woman was publicly flogged in April for having sexual relations outside marriage.